Internal combustion engines, including diesel engines, exhaust a complex mixture of potential air pollutants. These air pollutants may include solid material known as particulate matter or soot. Due to increased environmental concern, diesel engine exhaust emission standards have become increasingly stringent. The amount of particulate matter emitted from an engine may be regulated depending on the type of engine, size of engine, and/or class of engine.
One method implemented by engine manufacturers to comply with the regulation of particulate matter exhausted to the environment has been to remove the particulate matter from the exhaust flow of an engine using a device called a particulate trap or diesel particulate filter (DPF). A DPF is a filter designed to trap particulate matter in, for example, a wire mesh or ceramic honeycomb filtering media. Over time the particulate matter may accumulate in the filtering media, thereby reducing filter functionality and engine performance.
Various regeneration techniques may be employed to manage the accumulated particulate matter. For example, U.S. Pat. No. 6,488,725 (“the '725 patent”) issued to Vincent et al. on Dec. 3, 2002, describes a method of supplying an iron-containing fuel soluble additive for use in the regeneration of a particulate filter trap. The method includes supplying an additive to the fuel prior to combustion. In particular, the supply of additive is added into the fuel supply chain or is added via a dosing device on-board the vehicle to either the fuel tank, combustion chamber, or the inlet system. The additive mixes with the fuel, and the mixture is combusted to provide a flow of exhaust containing soot particulates and additives. In operation, the additives reduce the soot particulate ignition temperature. In this manner, the additives reduce the energy input required to initiate regeneration of the particulate filter.
Although the method described in the '725 patent may suitably regenerate the particulate filter trap, it may be problematic. In particular, as the additives travel through the fuel injectors of the engine, the additives may build-up in the injector tip. This may reduce the volumetric efficiency and spray pattern of the injectors. Furthermore, the additives may form a sediment in the combustion chamber of the engine thereby negatively affecting engine performance.
The system of the present disclosure solves one or more of the shortcomings set forth above and/or other shortcomings in the art.